1.0 Field of the Invention
This invention relates generally to paste containers, and more particularly to paste containers including dispensing mechanisms.
2.0 Discussion of Related Art
Paste-form detergents are growing in importance and are being increasingly used in laundries. Paste-form detergents have the advantages of powder-form detergents, especially their high active-ingredient contents, but none of the disadvantages of liquid detergents, especially their water or solvent contents. Paste-form detergents are often pseudoplastic or thixotropic pastes, more particularly high-viscosity detergent pastes, which are mainly used in institutional laundries.
Pseudoplastic or thixotropic pastes have the property whereby their viscosity is reduced by mechanical shearing, for example by stirring or shaking or under the effect of ultrasound, but is restored after removal of the mechanical stress. This means that this property whereby the viscosity of such pastes decreases under the effect of increasing shear stress or shear rate can be utilized to make handling easier. Unfortunately, these properties of paste-form detergents, especially high-viscosity pastes, also cause particular packaging and handling problems.
German patent application P 43 32 850 describes a paste container with a removal system which is suitable for accommodating and removing pastes. It consists of a cylinder open on one side and a tightly closing follower plate arrangement for displacement on the open side of the cylinder, and comprises a removal system for removing and transporting the paste. A geared motor is mounted on the follower plate, a multiple-blade propeller stirrer being arranged on the shaft of the motor which extends centrally through the follower plate. The propeller stirrer is positioned just below the follower plate, and is able to turn freely in the paste, the viscosity of the thixotropic paste being reduced under the shearing effect. The paste which thus becomes easy to transport is delivered by the propeller stirrer to a removal system which transports the paste through an opening in the follower plate, and which comprises an external drive mechanism.
This solution has the disadvantage that it is very expensive. The separate drives for the propeller stirrer and the removal system are expensive and, because of the space they require, are difficult to accommodate above the paste container.